CVE-2008-4475 in ibackup
Summary
by MITRE
ibackup 2.27 allows local users to overwrite arbitrary files via a symlink attack on temporary files.
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Analysis
by VulDB Data Team • 10/10/2018
The vulnerability identified as CVE-2008-4475 affects ibackup version 2.27 and represents a classic symlink attack scenario that exploits improper handling of temporary files during backup operations. This flaw enables local attackers to manipulate the system's file creation process by creating symbolic links that point to sensitive target files, thereby allowing unauthorized overwrites of critical system components or user data. The vulnerability stems from the backup utility's failure to properly validate or secure temporary file creation processes, creating an opportunity for privilege escalation and data integrity compromise.
The technical implementation of this vulnerability occurs when ibackup creates temporary files during its backup operations without adequately verifying the existence or ownership of these temporary files. Attackers can exploit this by pre-creating symbolic links with the same names that ibackup intends to use for temporary storage, effectively tricking the backup utility into writing data to locations controlled by the attacker rather than the intended temporary directories. This type of attack falls under the category of time-of-check to time-of-use race conditions, where the system checks for file existence at one point and then operates on that file at a different point, creating a window for exploitation.
From an operational perspective, this vulnerability presents significant risks to system integrity and data security, particularly in environments where backup utilities are executed with elevated privileges or where sensitive data is regularly backed up. Local users who can execute the ibackup utility can potentially overwrite critical system files, configuration data, or user documents, leading to system instability, data loss, or unauthorized access to sensitive information. The impact is particularly concerning because it allows attackers to manipulate the backup process itself, potentially creating backdoors or corrupting backup archives that could be used for further attacks.
The vulnerability aligns with CWE-377, which addresses insecure temporary file creation practices, and demonstrates how improper file handling can lead to privilege escalation and arbitrary file overwrite scenarios. Organizations should consider implementing mitigations such as ensuring that temporary files are created with proper permissions and unique naming conventions, using atomic file operations, and restricting the execution privileges of backup utilities. Additionally, system administrators should regularly audit backup processes and implement monitoring for unusual file creation patterns that might indicate symlink attacks. The ATT&CK framework categorizes this as a privilege escalation technique through file system manipulation, emphasizing the importance of proper file access controls and secure coding practices in system utilities.